flower genus, 1706, from Latin aster "star," from Greek aster (from PIE root *ster- (2) "star"); so called for the radiate heads of the flowers. Originally used in English in the Latin sense (c. 1600) but this is obsolete.

"pretender to philosophical knowledge," 1610s, from philosophy + -aster.

"mediocre musician," 1838, from music + -aster.

word-forming element expressing incomplete resemblance (such as poetaster), usually diminutive and deprecatory, from Latin -aster, from a suffix forming nouns from verbs ending in Greek -azein; in later Latin generalized as a pejorative suffix, as in patraster "he who plays the father."

"petty or contemptible historian," 1887, from historian with ending altered to -aster. Coined by W.E. Gladstone, in a review of J. Dunbar Ingram's "History of the Legislative Union of Great Britain and Ireland."

"a quack, a pretender to medical knowledge or skill," c. 1600, from Latin *medicaster (source also of Italian medicastro, French médicastre, 16c.), from medicus "physician" (from PIE root *med- "take appropriate measures") + -aster. The feminine form is medicastra.

"a petty, feeble, or contemptible politician" [OED], 1640s, from Italian or Spanish politicastro, from politico, noun use of adjective meaning "political" (from Latin politicus; see political) + pejorative ending (see -aster).

"one obstinate in asserting or adhering to his own opinions," c. 1600, from French opiniastre, from Latin opinio "opinion, conjecture" (see opinion) + deprecatory suffix (see -aster). Another word in a similar sense was opinator "opinionated person" (1620s), from Latin opinator "one who supposes or conjectures." Also opiniator (1520s).

"a petty poet, a feeble rhymster, a writer of indifferent verses," 1590s, from French poetastre (1550s), from Latin poeta (see poet) + French-derived -aster, a diminutive (pejorative) suffix. Old Norse had skaldfifl in roughly the same sense. Early modern English had rimester (1580s). Swinburne (1872) used poeticule. Related: Poetastry.

"person versed in or devoted to science," 1834, a hybrid coined from Latin scientia (see science) by the Rev. William Whewell, English polymath, by analogy with artist, in the same paragraph in which he coined physicist (q.v.). There is an isolated use of sciencist from 1778, and scientician was used in 1885. Scientaster "petty or inferior scientist" is by 1899 (see -aster).